To observe the effects of packaging methods and storage temperature on the water holding capacity (WHC) of beef, air-packaging(AP), modified atmosphere packaging(MAP) were used to package the longis-simus of beef and then these samples were stored under 2℃and-1.5℃. The pH, cooking loss, dripping loss and other indicators were detected at day 0,5,10,15 during the storage, as well as low field nuclear magnetic resonance technology(LF-NMR) was used to examine the water distribution and migration. The results showed that the rate of cooking loss and dripping loss increases, the relaxation time (T23) prolonged and content of im-mobile water (P22) decreased during the storage time. The analysis results of Pearson correlation coefficient showed that P22, T23 were significantly correlated with storage time, cooking loss and dripping loss (P<0.05 or P<0.01), indicating the extension of the relaxation time and the decrease of immobile water should be the direct cause leading to WHC decrease. The tests showed that the effect of packaging methods and storage temperature on the WHC of beef was significant(P<0.05), and the storage under controlled freezing-point and MAP could better maintain the WHC of beef.%以牛背最长肌为原材料,分别经托盘包装(AP)或气调包装(MAP)后贮藏于2℃及-1.5℃条件下,于贮藏第0、5、10、15天测定pH、蒸煮损失、汁液流失率等指标,并利用低场核磁共振技术(LF-NMR)考查水分分布状态及迁移规律,旨在探索不同包装方式及贮藏温度对牛肉保水性的影响.结果表明:随贮藏时间的延长,牛肉保水性下降,表现为蒸煮损失和汁液流失率增加,弛豫时间(T 23)延长和不易流动水含量(P 22)的减少.皮尔逊相关系数分析结果显示P 22、T 23与贮藏时间、蒸煮损失及汁液流失显著相关(P<0.05或P<0.01),表明弛豫时间的延长及不宜流动水的损失是导致保水性下降的直接原因.试验表明包装方式及贮藏温度对牛肉保水性影响显著(P<0.05),冰温贮藏及气调包装可较好的维持牛肉保水性.
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